In a printer apparatus used as an apparatus for issuing a receipt and the like, after given items are printed on long-sized paper pulled from roll-shaped paper, the printed paper is cut into a given length and then discharged.
As such a printer apparatus, a two-sided thermal printer is known which carries out printing on both sides (front side and back side) of the paper so as to decrease the consumption amount of paper.
The paper used in the two-sided thermal printer has heat-sensitive layers which generate a color when being heated on both sides (front side and back side) of the paper; however, the two-sided thermal paper serving as the paper used in the two-sided thermal printer is more expensive than the single-sided thermal paper having a heat-sensitive layer on one side only.
Therefore, it is not economically feasible to carry out printing only on one side of the two-sided thermal paper due to the high cost. However, as it takes a lot of trouble to switch and load the two-sided thermal paper and the single-sided thermal paper every time a printing job is carried out, it has been considered to load both the two-sided thermal paper and the single-sided thermal paper in one printer. It is also known how to detect the category of the paper so as not to carry out simplex printing on the two-sided thermal paper.
Even in a case where both the two-sided thermal paper and the single-sided thermal paper are loaded in one printer apparatus, when printing operation is carried out on one paper, it is necessary to retract the other paper on which printing operation is not carried out from the conveyance path, and in a case of frequently switching and using the two-sided thermal paper and the single-sided thermal paper, there exists a problem that much time is taken for the retracting processing and the printing speed of the printer is low.